


We Belong

by starkind



Series: Three Strong Hearts - A WonderIronBat Collection [4]
Category: Batman (Movies - Nolan), Iron Man (Movies), Wonder Woman (Movies - Jenkins)
Genre: Crossover Pairings, Crossovers & Fandom Fusions, Emotional Hurt/Comfort, Established Relationship, F/M, M/M, Multi, Not Canon Compliant, Polyamory, Protective Bruce Wayne
Language: English
Status: Completed
Published: 2020-05-15
Updated: 2020-05-15
Packaged: 2021-03-03 03:47:44
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,126
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24168343
Author URL: https://archiveofourown.org/users/starkind/pseuds/starkind
Summary: When a reaction leads to a realization, this leads to a whole new aspect of their relationship.Tony and Diana are used to Bruce's cryptic ways, but even they have not seen this coming.
Relationships: Diana (Wonder Woman)/Tony Stark/Bruce Wayne
Series: Three Strong Hearts - A WonderIronBat Collection [4]
Series URL: https://archiveofourown.org/series/1726759
Comments: 9
Kudos: 29





	We Belong

“We're leaving.”

Diana looked up to see Bruce's grave expression and put the champagne flute aside. “Already? We've just got here not even an hour ago.” He gave a strained smile. “Afraid so.” With one hand in the small of her back, he gently steered her towards the exit of the museum that hosted the current art exhibition. As soon as they were out of the main area, Bruce's pace increased, and Diana matched his stride despite wearing high heels.

“Did something happen? Where is Tony?”

When she glimpsed at his profile, she could see how Bruce's jaw was set at a very tight angle.

“Waiting outside.”

They reached the large foyer where a security guard opened one of the massive glass doors for them to exit. Before heading out into the night, Diana put a hand on her lover's arm. “What are you not telling me?” One of those fake smiles that never reached his eyes played on Bruce's lips as he let her pass through first.

“I'm just tired.”

Outside, Tony already stood waiting as Bruce had said. He was leaning against the open back door of a black limousine, and Diana frowned upon seeing him nursing a cigarette. Bruce said nothing and led her down the stairs towards him, the contact of his hand on her bare back a steady presence. Tony's mouth was askew around the object dangling from his mouth; eyes filled with a certain kind of reproach aimed at one person.

“Shouldn't have done that, B.”

Instead of an answer, Bruce took the cigarette from him with a nimble move and took a long drag.

“Don't care.”

Bluish fumes obscured his face as he focused on the woman in their midst. “Get in the car, it's cold.” Diana braced herself. Even with only the slightest ounce of her strength used, she was completely unmovable for either man. She made sure to cast them a dark glare. “If you don't tell me what's wrong right now, I'm not going anywhere.” Tony eyed his fast-disappearing cigarette in Bruce's hand with a look of remorse and sighed.

“B-boy here punched a member of the advisory board of the museum because of a stupid remark.”

While Diana cast bewildered eyes over to her other lover, Bruce forcefully exhaled another gust of smoke.

“He won't do it again, that's what's important.”

With that, he dropped the finished stub to the ground and crushed it under his black Italian Oxfords.  
  
“Let's go home.”

~

The drive to Stark Tower took less than twenty minutes. Bruce remained taciturn throughout the whole time, his frowning expression fixated on the streetlamps outside rushing by. Tony and Diana exchanged quiet glimpses ever so often, though neither of them made a move to break the silence.

Once they had arrived at the tower and the doors to the private penthouse had closed behind them, Bruce's reticence turned into frantic desire and culminated in a passionate encounter that left all of them sated and exhausted. In the dark of the bedroom, Diana's hand traveled over the familiar, scarred chest, feeling the erratic heartbeat under her palm slowly return to normal. “What did he say? The man you punched?”

Next to her, the blankets rustled, as Tony turned from his back over to his side and into their direction. Both waited patiently for their lover to finally put his woes into words. “You were both looking at the modern art section when he came up to warn me that my... escort was cozying up to that egomaniac playboy Stark. When I didn't react, he asked me if he could be next, and I just,” Bruce took a breath and forcefully exhaled.

“I just had to wipe that goddamn leer off his face.”

Diana's fingers curled and traveled up higher until she was able to cup and caress his jaw.

“Oh, Bruce.”

“Protecting our virtue's all kinds of hot and noble and a good look on you, honeybear, but you honestly should think a bit more about your rep.”  
  
Tony's baritone was a low rumble into the night. Bruce forced his jaw to unclench and he took Diana's hand off his face to press a kiss into her palm. “If there was a chance for statutory marriage between more than two people, believe me, I would-” He stopped, embarrassed, and cleared his throat. Tony sat up, his torso silhouetted against the city lights from outside the windows and the light of his ARC illuminating the three of them.

“Bruce Thomas Wayne, did you just propose to us after a round of mind-numbing sex?”

The latter's brows curved into a deep-set frown as he averted their gazes.

“No, I... no!”

Upon hearing his utterly rare fluster, Diana had to laugh out in bright, affectionate delight.

“I would marry the two of you in a heartbeat.”

Tony's grin, tinged in the blue hues of his reactor, widened.

“I'm game, too. Let's elope.”

After having regained most of his composure within seconds, Bruce propped himself up on an elbow and ran his free hand through his disheveled hair. “It's still illegal.” Diana made a telltale noise. “Then we'll do it ourselves. Just for us. Rings and vows. Small ceremony. No one needs to know. Or care.” Tony leaned back down to bodily drape himself over her, thus leaning closer to where Bruce was.

“And the engravings are gonna be in Themysciran so no one's any wiser.”  
  
Diana beamed at him, leading to them sharing a drawn-out, loving kiss that made Bruce's heart clench.

~

The next day after sleeping in and eating breakfast together, Tony sought out Bruce while Diana was in the private gym working out while also surfing the web with the help of Jarvis to pick out suitable rings. Bruce was sitting at the kitchen counter, nursing the last cup of coffee and typing on a notebook. “Bold move, babe. Never thought you'd be getting ahead of me.” Bruce stopped typing and glanced up at him.

“Don't tell me you've thought about this.”

A minuscule bout of insecurity flashed over Tony's face but was gone within a split second. “Mighta. I mean... nobody would see that coming from a guy like me, but... yeah. Mighta.” All chivalrous, Bruce pulled out the barstool next to him for Tony to join his side. “Diana will outlive us both, so I want to make sure she's well-situated in any case.” Tony slid onto the chair while simultaneously reaching for Bruce's cup and taking a sip.

“We're talking last will and stuff here?”

His lover gave a curt nod and took his cup back with deft fingers before it was empty. Tony hummed.

“She'll be richer than God with all of our assets combined.”

Bruce's sparse smirk was content.

“Good.”

**Author's Note:**

> Title is a song by Pat Benatar (1984)


End file.
